The reference design enables connectivity to the Alexa App on a Bluetooth 4.0 (and later) smartphone using a custom Bluetooth LE Audio Profile via the nRF51822 SoC. Enabled by the QuickLogic EOS S3 SoC’s hardware integrated Low Power Sound Detector (LPSD), the chip consumes just 640µW of power (in a typical use case) for ‘always-on’ listening and wake-word detection. When the voice prompt is recognized, the audio stream is compressed and transmitted over the nRF51822 SoC’s Bluetooth LE link to the smartphone. The smartphone then decompresses the audio data and sends it to the Alexa Voice Service (AVS) Cloud server. This results in the AVS server’s response being played over the smartphone speaker. A scheduled update will provide the option to have the response also played on a wearable device.

The Alexa BLE Wearables Reference Design supports the seamless transmission of Voice-over-Bluetooth LE, via a custom application developed by QuickLogic using Nordic’s nRF5 development tools. The application is stored in the nRF51822 SoC’s Flash memory, and buffers the voice data while the Bluetooth LE SoC wakes up. This intelligent power management, enabled by the QuickLogic EOS S3, further minimizes power consumption, while constantly monitoring for the voice activation trigger.

“We selected Nordic’s Bluetooth LE solution for its ultra low power wireless technology’s dominance in wearables as well as its interoperability with a wide range of smartphones and tablets,” says Brian Faith, QuickLogic’s CEO. “The low power consumption of the nRF51822 SoC enabled long battery life. In addition, the ease of use of Nordic’s software, as well as the company’s outstanding technical support, made us choose their technology again.”

“QuickLogic’s unique EOS MCU-based SoC with LPSD along with Nordic’s proven nRF51 Series hardware and software has enabled this new wearable reference design with Voice-over-Bluetooth LE,” says Svenn-Tore Larsen, Nordic Semiconductor’s CEO. “The collaboration has resulted in an offering that simplifies the development of a new class of voice-managed wearables, which we believe has the potential to enhance the lives of many people.”

About the EOS S3 Sensor Processing Platform

The EOS S3 Sensor Processing Platform is an ultra-low power, processing-efficient system which enables OEMs to extend battery life while designing in sophisticated, always-on sensing capabilities for mobile, wearable, hearable and IoT devices. The EOS S3 employs not only fundamental, but also very sophisticated, always-on, context-aware sensing capabilities while staying well within the strict power budgets of smartphone, wearable, hearable and IoT designs.